Brooklyn Brew Shop and BIAB

[_Bryan]

Howdy all,

I've been doing the Brooklyn Brew Shop 1 gallon all grain kits without any problems. I'd like to experiment with BIAB and since I have a BBS kit here, I'd like to try it with that.

My question is this, how much water should I start with? The kit has right at 2.4 pounds of grain. I've been reading that to calculate how much water you need, you can multiply by 1.25-2 quarts of water per pound of grain. Can anyone confirm this and narrow it down a bit?

Also, the kit instructions has a total of 6 quarts of water (between the mash and sparge), I'm wondering if this would be a good starting amount for BIAB. I'm guessing that it's too much though.

Thanks in advance!

 

[WayFrae]

When I BIAB I do full volume mashes.

You use however much water you normally start with to end up with 1 gallon post-boil. So, if you boil off 0.5 gal/hour then you will start with 1.5 gallons. Then add 0.1 gallons of water per pound of grain to compensate for absorption. If you have the boil-off rate listed above and 2 lbs of grain then you would start with 1.7 gallons of water.

 

[McKnuckle]

+1
Figuring out water volumes is an exercise in backtracking. Start with your desired amount in the fermenter, and add each predicted loss to that. This gives you the grand total volume of water. For BIAB, you will mash with that volume.

So if you want 1 gallon in the fermenter:

Add the amount you'll leave behind as trub when you pour from the kettle to the fermenter. If you pour the kettle out trub and all, that value is ZERO (and it's easier to work with IMHO).

Add the amount absorbed by hops in your recipe. This is quite small, perhaps 0.03 gal/oz of hops.

Then divide your subtotal at this point by 0.96. This compensates for the wort shrinkage that occurs when you cool it from a boil.

Next, add the amount you evaporate per hour times the number of hours you will boil.

Finally, add the amount that will be absorbed by the grain in the mash. For BIAB, 0.06 gal/lb is a reasonable amount.

You now have your starting total water volume! All that remains now is for you to figure out all of these variables! That's the "fun" part of tweaking a system. It will not be perfect for a few brews, but measure and take notes and you'll get it down.

 

[Thedutchtouch]

No need to divide by .96, starting volume is cold water, ending wort is cold. You only need to factor in wort shrinkage if you're comparing a boiling measurement with a cooled one. For brew in a bag, you typically start with full volume and heat it, no shrinkage calculation needed(like you would if you are transferring preheated water from a HLT).

You need to figure out your boil off rate, which is different for every pot/burner setup. Boil a gallon of water for a hour, cool it down, and see how much you have left. Done, easy. Then use the above replies to calculate your grain absorption.

 

[McKnuckle]

While I understand your point about cool liquid at the beginning and end, in practice there is a reasonably significant amount of "collateral evaporation" that occurs during brew day that is not otherwise accounted for. For example, while the mash, sparge, or kettle are heating up - and certainly post boil before the wort is fully cool. There's a lot of vapor risin', and I believe the 4% shrinkage loss compensates for it well. It's not covered by the standard evaporation/hr variable.

If I'm not mistaken, Beersmith includes this calculation in its water volumes tab.

 

[wilserbrewer]

IMO, the simplest approach is to measure / calibrate your kettle so you know how much volume you have in it as you progress.

For a 1 gallon batch, mash in one gallon, then sparge to reach preboil volume, around 1,5 gallon.

Knowing the volume in the kettle will allow you to make adjustments, low volume either sparge more (all wort must be boiled!) or top up w water. Too much volume boil longer and time late hops to flameout.

 

[ericbw]

The 6 quarts includes mash and sparge. So if you mash at 1.33 quarts per pound, that's 3.2 quarts. That would still leave you with 2.8 for the sparge.

Because of absorption, you'll lose a little more than a quart and end up with 5 quarts in the kettle. You'll boil off quite a bit and need to top up.

If anything, I would say the 6 quarts is too little.

As mentioned, you should calibrate your boil off rate. But assume at least 1/2 gallon per hour, and you need at least 6 quarts in the boil.